1. “Difference approximations for singular perturbations of ordinary differential equations”;Abrahamsson,1974
2. “An investigation into direct numerical methods for solving some calculus of variations problems. Part 1 – Second order methods”;Allen;Comp. J.,1966
3. “On the effective determination of the wave operator from given spectral data in the case of a difference equation corresponding to a Sturm-Liouville differential equation”;Andersson;J.M.A.A.,1970
4. “The feasibility of continuation methods for nonlinear equations”;Avila;SIAM J. Num. Anal.,1974
5. “Eigenvalues of singular differential operators by finite difference methods”;Baxley;J.M.A.A.,1972